The invention relates generally to an ink cartridge and a method of charging ink into the cartridge and more specifically to an ink cartridge and a method of charging ink into the cartridge suitable for an ink jet printer in which a carriage carries an ink jet recording head and an ink cartridge and in which the ink is replenished by replacing the cartridge.
In an ink jet printer in which the carriage carrying the ink jet recording head also carries an ink container, measures are taken to prevent pressure fluctuations of the ink due to the oscillation of the ink caused by the movement of the carriage, and defective printing due to foaming. That is, as proposed in Laid-open European Patent Publication No. 581531, the ink container of an ink jet printer is divided into two regions. A porous body is accommodated in a region on the recording head side, and ink is contained in the other region.
Such structure is advantageous in obviating inconvenience caused by the oscillation of the ink to a possible extent since the ink is supplied to the recording head through the porous body.
However, the porous body functions merely as a filter, and this means that it is the ink within the ink chamber, not the ink in the porous body, that substantially is the remaining amount of ink. Therefore, when the ink within the ink chamber runs out, the printer can no longer print. In addition, in a color printer or the like that uses inks of a plurality of colors, the amounts of remaining ink vary from one ink chamber to another even if the inks of all the colors have been supplied simultaneously since all the inks are not necessarily consumed equally in color printing. As a result, ink remains within the cartridge in liquid form when the cartridge is replaced, and when the cartridge is discarded the ink may leak out and contaminate the environment. In addition, the user may unnecessarily become apprehensive over unbalanced consumption of ink and the possibility of one of the colors running out.